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Biology subjects

Muraro, M.

Publications and source records attributed to Muraro, M..

5 recordsLinked to original sources

Latent plasticity of the human pancreas across development, health, and disease.

The pancreas plays a central role in major human diseases, yet our understanding of its cellular diversity and plasticity remains incomplete. Here, we present a single-cell multiomics atlas of the human pancreas, profiling over four million cells and nuclei from 57 donors across fetal development, adult homeostasis, and type 2 diabetes (T2D). Integrating sc/snRNA-seq, snATAC-seq, VASA-seq, spatial transcriptomics (Xenium), and multiplexed proteomics (CODEX), we resolve gene expression, chromatin accessibility, and spatial organization at high resolution. We identify transcriptionally plastic centroacinar-like cells (pCACs) in adults with fetal-like features, delineate endocrine and exocrine lineage trajectories during development, and uncover HNF1A-defined beta cell epigenetic states. In T2D, we observe shifts in beta cell subtypes and altered regulatory programs. Glucose perturbation of healthy islets reveals cell-type-specific adaptation and stress responses. This atlas provides a foundational framework to understand pancreas biology and the role of cellular plasticity in regeneration and disease.

genomics↗

Inflammatory Recruitment of Healthy Hematopoietic Stem and Progenitor Cells in the Acute Myeloid Leukemia Niche

Inflammation in the bone marrow (BM) microenvironment is a constitutive component of leukemogenesis in acute myeloid leukemia (AML). Current evidence suggests that both leukemic blasts and stroma secrete proinflammatory factors that actively suppress the function of healthy hematopoietic stem and progenitor cells (HSPCs). HSPCs are also cellular components of the innate immune system, and we reasoned that they may actively propagate the inflammation in the leukemic niche. In two separate congenic models of AML we confirm by evaluation of the BM plasma secretome and HSPC-selective single-cell RNA sequencing (scRNA-Seq) that multipotent progenitors and long-lived stem cells adopt inflammatory gene expression programs, even at low BM leukemic burden. In particular, we observe interferon gamma (IFN-{gamma}) pathway activation, along with secretion of its chemokine target, CXCL10. We show that AML-derived nanometer-sized extracellular vesicles (EVAML) are sufficient to trigger this inflammatory HSPC response, both in vitro and in vivo. Altogether, our studies indicate that HSPCs are an unrecognized component of the inflammatory adaptation of the BM by leukemic cells. The pro-inflammatory conversion and long-lived presence of HSPC in the BM along with their regenerative re-expansion during remission may impact clonal selection and disease evolution.

cancer biology↗

Functional single cell selection and annotated profiling of dynamically changing cancer cells

A method connecting single cell genomic or transcriptomic profiles to functional cellular characteristics, in particular time-varying phenotypic changes, would be transformative for single cell and cancer biology. Here, we present fSCS: functional single cell selection. This technology combines a custom-built ultrawide field-of-view optical screening microscope, fast automated image analysis and a new photolabeling method, phototagging, using a newly synthesized visible-light-photoactivatable dye. Using fSCS, we screen, selectively photolabel and isolate cells of interest from large heterogeneous populations based on functional dynamics like fast migration, morphological variation, small molecule uptake or cell division. We combined fSCS with single cell RNA sequencing for functionally annotated transcriptomic profiling of fast migrating and spindle-shaped MCF10A cells with or without TGF{beta} induction. We identified critical genes and pathways driving aggressive migration as well as mesenchymal-like morphology that could not be detected with state-of-the-art single cell transcriptomic analysis. fSCS provides a crucial upstream selection paradigm for single cell sequencing independent of biomarkers, allows enrichment of rare cells and can facilitate the identification and understanding of molecular mechanisms underlying functional phenotypes.

bioengineering↗

A metabolic switch from OXPHOS to glycolysis is essential for cardiomyocyte proliferation in the regenerating heart

The capacity to regenerate damaged tissues, such as the heart, various enormously amongst species. While heart regeneration is generally very low in mammals 1-3, it can regenerate efficiently in certain amphibian and fish species 4,5. Zebrafish has been used extensively to study heart regeneration, resulting in the identification of proliferating cardiomyocytes that drive this process 5-7. However, mechanisms that drive cardiomyocyte proliferation are largely unknown. Here, using a single-cell mRNA-sequencing approach, we find a transcriptionally distinct population of dedifferentiated and proliferating cardiomyocytes in regenerating zebrafish hearts. While adult cardiomyocytes are known to rely on mitochondrial oxidative phosphorylation (OXPHOS) for energy production, these proliferating cardiomyocytes show reduced mitochondrial gene expression and decreased OXPHOS activity. Strikingly, we find that genes encoding rate-limiting enzymes of the glycolysis pathway are induced in the proliferating cardiomyocytes, and inhibiting glycolysis impairs cardiomyocyte cell cycle reentry. Mechanistically, glycolytic gene expression is induced by Nrg1/Erbb2 signaling, and this is conserved in a mouse model of enhanced regeneration. Moreover, inhibiting glycolysis in murine cardiomyocytes abrogates the mitogenic effects of Nrg1/ErbB2 signaling. Together these results reveal a conserved mechanism in which cardiomyocytes undergo metabolic reprogramming by activating glycolysis, which is essential for cell cycle reentry and heart regeneration. This could ultimately help develop therapeutic interventions that promote the regenerative capacity of the mammalian heart.

cell biology↗

Fate Before Function: Specification of the Hair Follicle Niche Occurs Prior to its Formation and Is Progenitor Dependent

Cell fate transitions are essential for specialization of stem cells and their niches, but the precise timing and sequence of molecular events during embryonic development are largely unknown. Here, we show that dermal condensates (DC), signaling niches for epithelial progenitors in hair placodes, are specified before niche formation and function. With 3D/4D microscopy we identify unclustered DC precursors. With population-based and single-cell transcriptomics we define a molecular time-lapse of dynamic niche signatures and the developmental trajectory as the DC lineage emerges from fibroblasts. Co-expression of downregulated fibroblast and upregulated DC genes in niche precursors reveals a transitory molecular state following a proliferation shutdown. Waves of transcription factor and signaling molecule expression then consolidate DC niche formation. Finally, ablation of epidermal Wnt signaling and placode-derived FGF20 demonstrates their requirement for DC-precursor specification. These findings uncover a progenitor-dependent niche precursor fate and the transitory molecular events controlling niche formation and function.\n\nGraphical Abstract\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC=\"FIGDIR/small/414839_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (78K):\norg.highwire.dtl.DTLVardef@13fa73aorg.highwire.dtl.DTLVardef@1fbd280org.highwire.dtl.DTLVardef@1b8f66borg.highwire.dtl.DTLVardef@3a1ef9_HPS_FORMAT_FIGEXP M_FIG C_FIG HIGHLIGHTSO_LIPrecursors of the hair follicle niche are specified before niche cluster formation\nC_LIO_LIBulk/single cell RNA-seq defines early niche fate at molecular transitional state\nC_LIO_LISuccessive waves of transcription factor/signaling genes mark niche fate acquisition\nC_LIO_LINiche fate acquisition is not \"pre-programmed\" and requires FGF20 from progenitors\nC_LI

developmental biology↗